The biggest problem you will see is with dealer modified motors ......(the STAGE BOLT ON JUNK for the more money than brains club). Good 90 % of the problems are bolt on kits sold by the MOCO that are pure garbage. The tolerances are never checked by the techs doing the work at the dealers. Pistons and cyl scored too hell...over heating.Bent rods ..Luv that excuse...All blamed on oiling problems when truth be told it's the mass produced crap stage kits that the techs don't do the finish work on like a REAL engine builders does . But the more money than brains club wants a warranty and financing so they gets garbage work.
we have one guy here that had 4 -5 or maybe 10 motors supposedly blow up ...who knows.....even he has no clue. But it always gets blamed on what he thinks was oiling. If you have a dealer pull a brandnew motor apart. Your already in big trouble. Takes lots of time to,just blueprint a set of cyl and Pistons . Let alone pull heads apart.....check throttle plates.
Now this is my personal experance with dealer installed "STAGE" kits. Rings with end gap so tight is was never going to last .Next up rings installed upside down....overlap oil ring spacers.Pistons with .001 piston to wall clearance( could have just been honed to fix ) I have seen rods damaged from techs not supporting rods and just banging wrist pins in with a dead blow( witnessed)
I'll stop here on the install part. But so so so much more.
Now a halfa$$ed install goes bad in 500 miles motor is now full of shrapnel and the dealer will blow it out with air and brake clean. Guess what ? its gonna let go over and over again. The rite way a good engine builder does it...Complete Motor ,oil passages,oil pan / bag all need to be pulled down to nothing. Next up oil coolers and lines go in trash...they can't be cleaned. Than u have the poor bas tard that does have a bad oil pump get lumped into the same pile. It's rare but does happen . Get away from the forums and ask the actual owners if m8s ..... 97% of them are gonna tell u only problem?
stop smiling and keeeeeeping the damn gas tank full. Lmao!!! Go get one you'll enjoy it like most of us do.....

Same is true for Stage IV. Some of the comments being made about the power increases on a stage IV are simply clueless. The power of a Stage IV comes on at 3000+rpms. The biggest difference compared to stock is because the stock engine is utterly dead above 4000 rpms while a stage IV continues to increase in hp. But the Stage IV is still a dramatic increase at 3000rpms and above.

Once you’ve ridden a bike with a stage IV, you’ll never be satisfied with a stock bike.